Fixed some broken things related to context help, fixed memory leak

in wxGenericTreeCtrl (Init should be called before Create, not _in_ Create)


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@8295 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/window.cpp

@@ -3777,6 +3777,8 @@ wxPoint wxGetMousePosition()
 
     int x, y;
     GdkWindow* windowAtPtr = gdk_window_at_pointer(& x, & y);
+    if (!windowAtPtr)
+      return wxPoint(-999, -999);
 
     Display *display = GDK_WINDOW_XDISPLAY(windowAtPtr);
     Window rootWindow = RootWindowOfScreen (DefaultScreenOfDisplay(display));